1. Field of the Invention
The present invention relates to a substrate material bearing a printed image facing outwards with respect to the container on which the lid material is used, and an inward facing sealing layer for closing off containers having a shoulder region.
2. Background Art
It is known to provide a ring-shaped shoulder at the opening to containers such as e.g. deep-drawn or stretch-drawn containers or containers formed in another manner, and to lid such containers in particular after filling, such that the lid lies over the whole of the shoulder and is securely attached and sealed to the shoulder by sealing or adhesive bonding. Such beakers, dishes, menu dishes e.g. with one or more compartments, goblets, small packs etc. are e.g. known for packaging all kinds of food stuffs such as e.g. milk products, especially yogurts, whipping cream, sour milk, sour cream, coffee cream, ready-made salads or partially or fully conserved foods, pre-cooked or otherwise prepared dishes, drinks such as fruit and vegetable juices, drinking water etc.
As a rule the containers are filled and the lid material fed from an endless roll over the containers to be lidded which are continuously fed into a packaging machine. The lid material which features a sealing layer is sealed to the shoulder region at the rim of the container by means of a sealing tool. Subsequently, the lid material is cut away e.g. by means of a stamping tool or cutting blade, and the filled, lidded container packed and dispatched for sale individually or individually in groups.
The lid material may be made of a wide range of materials which depend on the requirements to be met. Typical examples are metal foils coated with plastic on one or both sides. Other lid materials are thermoplastics in the form of monofilms or multilayer laminates. Further lid materials may be of cellulose containing materials such as cellophane or paper. In order to seal the lid material to the rim of the container, the lid material is covered over its whole surface area by sealing layer such as an organic sealing coating or sealing film, whereby the sealing layer is deposited e.g. on both sides of the lid material or at least on the side facing the interior of the finished packaging i.e. towards the interior of the container.
The lid material also serves as substrate for carrying information and advertising. For that reason the lid material is provided on the outside with a printed image or reversed-image. The printing may be situated on the uppermost layer i.e. the layer facing outwards on the final container. The printing may also be covered with a protective organic coating or a protective film or, the uppermost layer or layers of the lid material may be of transparent or opaque materials and bear a reversed image. The printed images may be single or multi-coloured and deposited in a printing machine.
The lid material is manufactured e.g. such that a substrate such as a metal foil, a plastic film or a plastic film laminate is made by laminate bonding or calendering one or more layers into a multilayer laminate. The sealing layer is deposited as an organic coating or by laminate bonding on the side of the lid material facing the interior of the container. Following that, the lid material--which is e.g. in roll form--is fed into a printing machine. A further image may be printed later onto the side of the lid material facing outwards.
The disadvantage of these known methods for producing lid materials is the large number of steps involved in their preparation, in particular the high expenditure for materials for completely covering the lid material with sealing material, although only a small percentage of this sealing material is finally used for sealing purposes.